Document Detail


Spinal glutamatergic NMDA-dependent cyclic pelvic nerve-to-external urethra sphincter reflex potentiation in anesthetized rats.
MedLine Citation:
PMID:  17376759     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The purposes of this study were to investigate whether the pelvic nerve-to-external urethra sphincter (EUS) reflex potentiation can be induced under physiological conditions and to determine whether glutamatergic neurotransmission is involved in the reflex potentiation. Stimulation-evoked reflex activities, during rhythmic bladder contractions caused by a continuous saline infusion, in 21 anesthetized rats were recorded with/without the intrathecal administration of 10 microl of CNQX (a glutamatergic AMPA receptor antagonist; 100 microM) and APV( a glutamatergic NMDA receptor antagonist; 100 microM). Reflex activities became potentiated following the increment of intravesical pressure (IVP) during the storage phase (2.39 +/- 0.28 spikes/mmHg, n = 21) and the ascending period of the voiding phase (1.46 +/- 0.35 spikes/mmHg, n = 21) and decreased following the decrement of IVP during the descending period of the voiding phase (1.50 +/- 0.33 spikes/mmHg, n = 21). Although it is characterized by a low IVP, a postvoiding reflex potentiation in stimulation-evoked activities was elicited at the critical period after a voiding contraction had just finished (23.95 +/- 8.96 spikes/mmHg, n = 21). The slope of the regression line of evoked activities vs. the IVP during the storage phase was significantly (P < 0.01) higher than that of the ascending and descending periods of the voiding phase, but there was no statistical difference between the ascending and the descending periods (P > 0.05). In addition, the slope of the regression line of posttetanic reflex potentiation was significantly higher than that of the storage phase (P < 0.01). All the slopes of the regression lines decreased after intrathecal CNQX administration (from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.83 +/- 0.31, 0.74 +/- 0.12, 0.76 +/- 0.12, and 4.31 +/- 3.71 spikes/mmHg in storage, ascending and descending period of the voiding phase, and postvoiding potentiation, respectively; all P < 0.01, n = 10). The slopes of the regression lines became almost horizontal after intrathecal APV administration (from 3.15 +/- 0.44, 2.10 +/- 0.57, 2.13 +/- 0.53, and 21.30 +/- 3.41 to 0.16 +/- 0.12, 0.21 +/- 0.07, 0.18 +/- 0.05, and 0.23 +/- 0.76 spikes/mmHg in storage, ascending and descending period of voiding phase, and postvoiding potentiation, respectively; all P < 0.01, n = 10). Our results suggest that a potentiation in the pelvic nerve-to-EUS reflex can be induced under physiological conditions and the glutamatergic mechanism appears to be involved in this reflex potentiation.
Authors:
Jiuan-Miaw Liao; Cho-Hsun Yang; Chen-Li Cheng; Shwu-Fen Pan; Mei-Jung Chen; Pei-Chen Huang; Gin-Den Chen; Kwong-Chung Tung; Hsien-Yu Peng; Tzer-Bin Lin
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-03-20
Journal Detail:
Title:  American journal of physiology. Renal physiology     Volume:  293     ISSN:  1931-857X     ISO Abbreviation:  Am. J. Physiol. Renal Physiol.     Publication Date:  2007 Sep 
Date Detail:
Created Date:  2007-08-31     Completed Date:  2007-10-29     Revised Date:  2011-04-28    
Medline Journal Info:
Nlm Unique ID:  100901990     Medline TA:  Am J Physiol Renal Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  F790-800     Citation Subset:  IM    
Affiliation:
Department of Physiology, College of Medicine, Chung-Shan Medical University Hospital, Chung-Shan Medical University, Taichung, Taiwan.
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MeSH Terms
Descriptor/Qualifier:
Action Potentials
Anesthesia
Animals
Electromyography
Electrophysiology
Female
N-Methylaspartate / metabolism*
Pelvis / innervation*
Peripheral Nerves / physiology*
Rats
Rats, Wistar
Reflex / physiology*
Spinal Cord / physiology
Urethra / innervation*
Chemical
Reg. No./Substance:
6384-92-5/N-Methylaspartate

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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